Physicians and veterinarians frequently rely on methods of dilatation of a natural opening in a body (e.g., the urethra) to gain greater access to internal areas of the body without making an incision and cut through tissue of the body. A not infrequent purpose of this procedure of dilating a cavity, canal, duct, blood vessel or other bodily opening is to enlarge the opening so as to permit the insertion of instruments through the opening for visualization, tissue sampling, or therapeutic treatment of areas of the body accessible through the opening.
Conventional devices for effecting dilatation in a body include sized metal rods with fixed angles. Other such devices are metallic instruments that can be bent to conform to a selected portion of the body. Still other conventional dilators are made of malleable polymeric material.
A serious drawback of these conventional devices recognized by Applicants is that they necessitate the physician's estimating how far into the body the device extends and where within the body the device is positioned. This limitation forces a physician using such a device to slowly probe with the tip of the device inside a patient's body as the device is inserted into the body. Accordingly, the physician must rely largely on tactile sensations to judge whether the instrument is being properly maneuvered within the patient's body. This poses the ever-present risk that if the physician misjudges the position of the dilatation device, the wall of cavity or organ may be perforated.
Another drawback of these conventional devices recognized by Applicants is that they pose a difficult economic choice in the sense that each dilatation device must be either disposed of after only one use—in which case, each such device will need to be relatively inexpensive to manufacture—or otherwise it must be sterilized. Sterilization is a consideration that must be addressed with any reusable medical device, but is especially pertinent with respect to those used in invasive procedures. Viruses and bacteria can be trapped on the surfaces of such devices. Moreover, the lubricants applied during the use of such devices, if they remain on the device's surface, can trap microbes on the surface. If the devices are to be reused safely, some means of sterilizing the devices are an absolute essential. Sterilization methods are available for reusable medical devices. Heat or chemicals such as glutaraldehyde can be used. These methods, however, can be expensive and can reduce the operative life of the instrument. Moreover, there is a growing recognition by others that repeated use of antibiotics for sterilization (and other) purposes can reduce their effectiveness. The only alternative to sterilization, therefore, is to make the device completely disposable. Applicants have also recognized, however, that disposable can be out of the question from a purely economic standpoint if the device is to include the advanced features needed to overcome the limitations of conventional dilatation devices.
Accordingly, there is a need for a dilator that can be accurately guided through tortuous actual and potential spaces, canals, and cavities of the body without relying on elaborate structures and mechanisms that would make disposal or sterilization of the device cost prohibitive.